Coupling effect of solenoid in CSRm

The principle of particle coupling between horizontal and vertical directions in solenoid is presented. Further more, the method of decoupling can be obtained by using the coupling dynamic equations. 5000 particles are tracked under three conditions: CSRm doesn't contain solenoids, contains main solenoid and toroids, contains compensating solenoids. The results of the particle trace calculations show that the particles coupling between horizontal and vertical is very serious because of the existence of solenoids, and lot's of particals are lost. Another two solenoids which locate in the fit place can be used to decrease the coupling intensation. The method is proved to be useful by the trace calculations.

高品质CsI晶体研制及HPLUS谱仪中电磁量能器模拟

在HIRFL-CSRm的强子物理谱仪(HPLUS)中，电磁量能器(EMC)是其非常重要的组成部分之一。计划中的电磁量能器将使用CsI(Tl)晶体搭建，主要用于高能γ射线和电子的探测，共需要约1020根晶体单元探测器，总重量约3500～5000公斤。另外，我们还计划在CSRm的外靶实验终端建造一个可测量单个射线、所有射线的能量求和以及多重性的γ球探测器，该探测器预计使用CsI(Tl)晶体，总重量约1700公斤。鉴于近代物理所对CsI晶体的大量需求，我们启动了自行研制大尺寸CsI晶体的计划。目前，我们已经掌握了利用Bridgman晶体生长技术，生长出高品质、大尺寸CsI晶体（~100mm×350mm）的工艺。同时我们也掌握了各种不同尺寸和形状的CsI晶体加工工艺。测试结果表明，自行研制的CsI(Tl)晶体的多项指标均好于其他厂家的同类产品。本论文工作的主要内容有：（1）高品质、大尺寸CsI晶体生长工艺的摸索；（2）自制CsI晶体性能的系统测试，包括：光产额的温度效应、PD/APD读出时的能量分辨(源测试)、表面处理和光输出的关系、包装材料的选择、光输出非均匀性、辐照硬度等，以及自制CsI(Tl)晶体在重离子物理实验中的应用等；（3）基于GEANT4软件包，建立了CsI(Tl)晶体探测器的模拟程序，模拟主要集中在对影响单元探测器性能的因素进行分析，包括：侧面泄露、尾部泄露、包装材料的类型和厚度、提前簇射、晶体光输出非均匀性等。建立了EMC探测器的模拟框架，并通过模拟初步确定了HPLUS中EMC探测单元尺寸和和探测单元数目，为EMC设计的优化以及HPLUS的整体模拟打下了重要的基础

Cr/Al系统的离子束混合

用600kev的kr~+对Cr/Al薄膜系统进行了离子束混合研究。实验样品是在单晶硅上蒸镀约5000 A厚的铝膜，相继再上所需不同厚度的铬膜。Kr~+注入剂量范围在2.0 * 10~(15)～2.5 * 10~(16) kr~+/cm~2之间。用2.0 Mev的α粒子对注入前后的样品进行了背散射分析，发现铝谱的前沿和铬谱的后沿有明显的展宽，且随剂量的增大而加宽，Cr/Al界面原子混合扩展量的平方α~2注入剂量φ成线性关系；当注入剂量大于1.0 * 10~(16) kr~+/cm~2时，铝谱前沿和铬谱的后沿出现有明显的平坦，经理论拟合计算，发现有化合物形成，x射线衍射实验结果证明化合物形式为Al_(13)Cr_2。本文还得到了混合量Q与剂量的线性关系。最后，对混合机制进行了讨论

Direct reduction of SO2 to elemental sulfur by the coupling of cold plasma and catalyst (I)

The direct reduction of SO2 to elemental sulfur in flue gas by the coupling of cold plasma and catalyst, being a new approach for SO2 reduction, was studied. In this process, CO2 can be disassembled to form CO, which acts as the reductant under the cold plasma. With the coupling of the cold plasma and the catalyst, sulfur dioxide was selectively reduced by CO to elemental sulfur with a byproduct of metal sulfate, e.g., FeSO4. In the present work, Fe2O3/gamma-Al2O3 was employed as the catalyst. The extent of desulfurization was more than 80%, and the selectivity of elemental sulfur is about 55%. The effects of water vapor, temperature, and the components of simulated flue gas were investigated. At the same time, the coupling of thermogravimetry and infrared method and a chemical analysis method were employed to evaluate the used catalyst. In this paper, we will focus on the discussion of the catalyst. The discussions of the detail of plasma will be introduced in another paper.

Boundary Characterization Experiment Series Overview

Ocean acoustic propagation and reverberation in continental shelf regions is often controlled by the seabed and sea surface boundaries. A series of three multi-national and multi-disciplinary experiments was conducted between 2000-2002 to identify and measure key ocean boundary characteristics. The frequency range of interest was nominally 500-5000 Hz with the main focus on the seabed, which is generally considered as the boundary of greatest importance and least understood. Two of the experiments were conducted in the Mediterranean in the Strait of Sicily and one experiment in the North Atlantic with sites on the outer New Jersey Shelf (STRATAFORM area) and on the Scotian Shelf. Measurements included seabed reflection, seabed, surface, and biologic scattering, propagation, reverberation, and ambient noise along with supporting oceanographic, geologic, and geophysical data. This paper is primarily intended to provide an overview of the experiments and the strategies that linked the various measurements together, with detailed experiment results contained in various papers in this volume and other sources

21世纪中国历史地理学发展的思考

本文在回顾中国历史与近50年来取得的巨大成就的基础上,结合当今地球系统科学、地理科学的发展趋势以及国际全球变化与可持续发展研究的最新动向,提出了新世纪中国历史地理学研究应以收集、发掘人类文明演进的地理证据,分析历史上人地交互作用的时空特征为核心,以探寻当今地理学历史渊源人类适应环境变化模式的历史证据为目标,以文献分析、野外调查、考古发掘等传统方法与现代实验技术、空间信息技术的集成为手段,以编制5000年来华夏故土嬗变与文明演进的历史图谱为主要平台的发展新思路,并认为中国历史地理学在国际全球变化与可持续发展

Changes in individual plant traits and biomass allocation in alpine meadow with elevation variation on the Qinghai-Tibetan Plateau

Plant traits and individual plant biomass allocation of 57 perennial herbaceous species, belonging to three common functional groups (forbs, grasses and sedges) at subalpine (3700 m ASL), alpine (4300 m ASL) and subnival (>= 5000 m ASL) sites were examined to test the hypothesis that at high altitudes, plants reduce the proportion of aboveground parts and allocate more biomass to belowground parts, especially storage organs, as altitude increases, so as to geminate and resist environmental stress. However, results indicate that some divergence in biomass allocation exists among organs. With increasing altitude, the mean fractions of total biomass allocated to aboveground parts decreased. The mean fractions of total biomass allocation to storage organs at the subalpine site (7%+/- 2% S.E.) were distinct from those at the alpine (23%+/- 6%) and subnival (21%+/- 6%) sites, while the proportions of green leaves at all altitudes remained almost constant. At 4300 m and 5000 m, the mean fractions of flower stems decreased by 45% and 41%, respectively, while fine roots increased by 86% and 102%, respectively. Specific leaf areas and leaf areas of forbs and grasses deceased with rising elevation, while sedges showed opposite trends. For all three functional groups, leaf area ratio and leaf area root mass ratio decreased, while fine root biomass increased at higher altitudes. Biomass allocation patterns of alpine plants were characterized by a reduction in aboveground reproductive organs and enlargement of fine roots, while the proportion of leaves remained stable. It was beneficial for high altitude plants to compensate carbon gain and nutrient uptake under low temperature and limited nutrients by stabilizing biomass investment to photosynthetic structures and increasing the absorption surface area of fine roots. In contrast to forbs and grasses that had high mycorrhizal infection, sedges had higher single leaf area and more root fraction, especially fine roots.

Highly 3,4-selective living polymerization of isoprene with rare earth metal fluorenyl N-heterocyclic carbene precursors

Fluorenyl modified N-heterocyclic carbene ligated rare earth metal bis(alkyl) complexes, (Flu-NHC)Ln(CH2SiMe3)2 (Flu-NHC = (C13H8CH2CH2(NCHCCHN)C6H2Me3-2,4,6); Ln = Sc (1a); Ln = Y (1b); Ln = Ho (1c); Ln = Lit (1d)), were synthesized and fully characterized by NMR and X-ray diffraction analyses. Complexes Ib-d with the activation of (AlBu3)-Bu-i and [Ph3C][B(C6F5)4] exhibited high activity, medium syndio-but remarkably high 3,4-regio-selectivity, and the unprecedented livingness for the polymerization of isoprene. Such distinguished catalytic performances could be maintained under various monomer-to-initiator ratios (500-5000) and broad polymerization temperatures (25-80 degrees C).

温度敏感性PNIPAM-b-PZLL-b-mPEG三嵌段共聚物的合成与自组装研究

通过大分子引发剂引发ε-苄氧羰基-L-赖氨酸-N-羧酸酐(Lys-NCA)开环聚合和大分子缩合的方法合成了聚(N-异丙基丙烯酰胺)-b-聚(ε-苄氧羰基-L-赖氨酸)-b-聚乙二醇单甲醚三嵌段共聚物(PNIPAM-b-PZLL-b-mPEG).用GPC和1H-NMR对其结构进行了表征.用芘荧光探针法证明了该三嵌段聚合物形成胶束的性质并测定了临界胶束浓度(CMC).动态光散射(DLS)研究表明,在固定PNIPAM-b-PZLL链段长度的情况下,mPEG分子量为2000时,胶束在温度高于临界溶解温度(LCST)时发生聚集,mPEG分子量为5000时,胶束在LCST以上没有发生聚集.

SYNTHESIS AND CHARACTERIZATION OF A CROSSLINKING POLYETHYLENIMINE AS SMART GENE CARRIER AND EFFECTS OF PEGYLATION DEGREE

A smart biodegradable cationic polymer (CBA-PEI) based on the disulfide bond-containing cross-linker cystamine bisacrylamide (CBA) and low molecular weight branched polyethylenimine (1800-Da, PEI1800) was successfully synthesized by Michael addition reaction in our recent study. Furthermore, a series of copolymers (CBA-PEI-PEG) with different PEGylation degree were obtained by the mPEG-SPA (5000-Da) reacting with CBA-PEI at various weight ratios directly. The molecular structures of the resulting polymers CBA-PEI and CBA-PEI-PEG were evaluated by nuclear magnetic resonance spectroscopy (H-1-NMR) and capillary viscosity measurements, all of which had successfully verified formation of the copolymers. The polymer/DNA complexes based on CBA-PEI and CBA-PEI-PEG were measured by dynamic light scattering and gel retardation assay. The results showed that the particle size and zeta potential of complexes were reduced with increasing amount of PEG grafting, even no particle formation. The particle size of CBA-PEI/DNA complexes was in range of 103.1 to 129.1 nm, and the zeta potential was in range of 14.2 to 24.3 mV above the 2:1 weight ratio. In the same measure condition, the particle size of CBA-PEI-PEG complexes was reduced to a range of 32.2 to 55 nm, and the zeta potential was in range of 9.3 to 13.8 mV at the 2:1 weight ratio.

Preparation and chracaterization of novel graft copolymers of LLDPE

A series of novel fluorine surfactants, a, b, c, d, e and their acrylates, A, 13, C, D and E, were synthesized via poly( ethylene oxide) ( PEG) ( 200, 600, 1000, 2000, 5000) and perfluorooctane poly (ethylene oxide) ether as the main starting materials. Their chemical structures were characterized by means of FTIR and H-1 NMR. The surface activity and surface tension( y) of surfactants a, b, c, d and e were evaluated by maximum bubble pressure method. Surfactants A, 13, C, D and E were adopted as the grafting monomers of linear low density polyethere( LLDPE), and grafting reaction was carried out by melt reactive extrusion procedure. Their surface properties were characterized with measuring contact angle and XPS. It was found that the hydrophilic property of the graft copolymers was better than the palin LLDPE. Thermal properties of graft copolymers were studied by DSC. It was found that their crystalline temperatures of graft copolymers were faster than that of the plain LLDPE.

Study of the synthesis, crystallization, and morphology of poly(ethylene glycol)-poly(is an element of-caprolactone) diblock copolymers

Poly(ethylene glycol) -poly(epsilon-caprolactone) diblock copolymers PEG-PCL were synthesized by ring-opening polymerization of c-caprolactone using monomethoxy poly(ethylene glycol) as the macroinitiator and calcium ammoniate as the catalyst. Obvious mutual influence between PEG and PCL crystallization was studied by altering the relative block length. Fixing the length of the PEG block (M-n = 5000) and increasing the length of the PCL block, the crystallization temperature of the PCL block rose gradually from I to about 35 degreesC while that of the PEG block dropped from 36 to -6.6 degreesC. Meanwhile, the melting temperature of the PCL block went up from 30 to 60 degreesC, while that of the PEG block declined from 60 to 41 degreesC. If the PCL block was longer than the PEG block, the former would crystallize first when cooling from a molten state and led to obviously imperfect crystallization of PEG and vice versa. And they both crystallized at the same temperature, if their weight fractions were equal. We found that the PEG block could still crystallize at -6.6 degreesC even when its weight fraction is only 14%. A unique morphology of concentric spherulites was observed for PEG5000-PCL5000.

Highly efficient pure-white-light-emitting diodes from a single polymer: Polyfluorene with naphthalimide moieties

Light-emitting diodes exhibiting efficient pure-white-light electroluminescence have been successfully developed by using a single polymer: polyfluorene derivatives with 1,8-naphthalimide chromophores chemically doped onto the polyfluorene backbones. By adjusting the emission wavelength of the 1,8-naphthalimide components and optimizing the relative content of 1,8-naphthalimide derivatives in the resulting polymers, white-light electroluminescence from a single polymer, as opposed to a polymer blend, has been obtained in a device with a configuration of indium tin oxide/poly(3,4-ethyleiledioxythiophene)(50 nm)/polymer(80 nm)/Ca(10 nm)/Al(100 nm). The device exhibits Commission Internationale de I'Eclairage coordinates of (0.32,0.36), a maximum brightness of 11900 cd m(-2), a current efficiency of 3.8 cd A(-1), a power efficiency of 2.0 lm W-1. an external quantum efficiency of 1.50 %, and quite stable color coordinates at different driving voltages, even at high luminances of over 5000 cd m(-2).

Composition dependence of the crystallization behavior and morphology of the poly(ethylene oxide)-poly(epsilon-caprolactone) diblock copolymer

The crystallization behavior and morphology of the crystalline-crystalline poly(ethylene oxide)-poly(epsilon-caprolactone) diblock copolymer (PEO-b-PCL) was studied by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), Fourier transform infrared spectroscopy (FTIR), small-angle X-ray scattering (SAXS), and hot-stage polarized optical microscope (POM). The mutual effects between the PEO and PCL blocks were significant, leading to the obvious composition dependence of the crystallization behavior and morphology of PEO-b-PCL. In this study, the PEO block length was fixed (M-n = 5000) and the weight ratio of PCL/PEO was tailored by changing the PCL block length. Both blocks could crystallize in PEO-b-PCL with the PCL weight fraction (WFPCL) of 0.23-0.87. For the sample with the WFPCL of 0.36 or less, the PEO block crystallized first, resulting in the obvious confinement of the PCL block and vice versa for the sample with WFPCL of 0.43 or more. With increasing WFPCL, the crystallinity of PEO reduced continuously while the variation of the PCL crystallinity exhibited a maximum. The long period of PEO-b-PCL increased with increasing WFPCL from 0.16 to 0.50 but then decreased with the further increase of WFPCL due to the interaction of the respective variation of the thicknesses of the PEO and PCL crystalline lamellae.

Influence of crystal structure on the luminescence properties of bismuth(III), europium(III) and dysprosium(III) in Y2SiO5

The luminescence properties of Bi3+, EU(3+), Dy3+ and energy transfer from Bi3+ to Dy3+ and EU(3+) have been studied in two modifications of Y2SiO5 (low-temperature X(1) type and high-temperature X(2) type) and discussed in relation to their crystal structures. The Bi3+ ion luminesces in the blue region of the spectrum in X(1)-Y2SiO5 but in the UV region in X(2)-Y2SiO5. Two obviously different luminescent centres have been observed for Bi3+ and Eu3+ ill X(1)-Y2SiO5, but only one has been seen in X(2)-Y2SiO5. The Stokes shift (9200 cm(-1)) for Bi3+ in X(1)-Y2SiO5 is much larger than that (5000 cm(-1)) in X(2)-Y2SiO5. This suggests that the host lattice is more rigid in X(2)-Y2SiO5 than in X(1)-Y2SiO5. As a result, the Bi3+, EU(3+) and Dy3+ ions show higher emission intensity in the former than in the latter type. X(1)-Y2SiO5 is more suitable for Bi3+ --> EU(3+) energy transfer and X(2)-Y2SiO5 is more suitable for Bi3+ --> Dy3+ energy transfer.